PERMEABILITY TESTING OF PLASTIC CONCRETE

Conventional permeability tests on hardened concrete suffer some limitations such as uncertainty of the physics governing the flow. These tests are painstaking and expensive and yield inconsistent results. Testing concrete at the plastic stage is proposed as a way of rationalizing and accelerating the test. As a first step toward full realization of this concept, the permeability characteristics of retarded plastic concrete have been investigated by using a specially designed cell and a falling-head permeameter. During this investigation, particular attention was paid to (a) elimination of the effect of boundary flow on the true values of the coefficient of permeability of the permeate; (b) verification of the validity of Darcy's law for flow-through plastic concrete; and (c) evaluation of the effects of variation in water-cement ratios and the hydration process on values of the coefficient of permeability of the permeate. Results so far available confirm that the Darcy flow is applicable to plastic concrete. The Darcy coefficient of permeability of the mixes used in this project is generally of the order of 10 exp -5 cm/s and increases exponentially as the water-cement ratio increases. The effect of addition of sugar, as a retarder, is to reduce values of the coefficient of permeability of the permeate. Similarly, hydration reduces the coefficient of permeability of the permeate, which decreases with time.

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 93-103
  • Monograph Title: Recent developments in accelerated testing and maturity of concrete
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00131697
  • Record Type: Publication
  • ISBN: 0309024668
  • Files: TRIS, TRB
  • Created Date: Jun 5 1976 12:00AM